1. Technical Field
This invention relates generally to the field of electrophotographic printing. More specifically, this invention relates to improving the print quality of non-saturated colored text and lines in eletrophotographic printing processes.
2. Description of the Related Art
In the context of electrophotographic printing, the current process for rendering text or graphics that are not one hundred percent saturated (non-saturated) is through conventional half-tone screening techniques. For the purposes of discussion herein, saturation refers to 100% area coverage in a given region of the printer's primary colorants: Cyan, Magenta, Yellow and/or Black (CMYK). Also, for the purposes of discussion herein, half-toning may be defined as a pattern of dots or as a process that achieves a perceived continuous tone imager through the use of dots, varying either in size, in shape or in spacing. One common technique of half-toning is amplitude modulation screening (“AM screening”). For the purposes of discussion herein, AM screening may be described as a process by which the size of a given dot varies, reflecting the density of the object that it represents and by which the dots are placed in a grid.
Examples of AM screening techniques employ dot screens and line screens, where the increase in darkness is achieved by adding more ink to some spots or some lines on the given piece of paper. AM screening may behave as though a sine wave is propagating through the target area, where the intensity or other characteristic goes up and down. However, it should be appreciated that on average, the human eye perceives the right color, the color that is meant to be conveyed.
While electrophotographic printing of non-saturated colors may render the intended color, at least to the human eye, it has been found that electrophotographic printing of non-saturated colors using AM screening may also lead to jagged edges of text and lines. Thus, it would be desirable that, when printing text or lines in non-saturated colors on electrophotographic printers, the printing process does not render jagged edges for the printed text or lines.